Determination of stability constant of complexes and purity of organic reagents by spectrophotometric method

A new method for determining the stability constant of complex and purity of organic reagent is suggested. The complex's apparent stability constants first determined by mole ratio method, followed by the treatment of material balance and linear regression, purity of reagent and stability constant of complex can be determined at the same time. The method was used to the 4-(5-Cl-2-pyridylazo)-1, 2-diaminobenzene (5-Cl-PADAB) and CO(II) system, and the satisfactory results was obtained.